Police fired tear gas to break up a protest in Senegal's capital Dakar on Thursday and arrested several people, including a former premier, protesting against a move to raise the bar for presidential candidates.

With less than a year to go before the presidential election, the government wants to increase the number of signatures candidates must collect in order to stand for president — which the opposition says is aimed at limiting and controlling opposition.

Two opposition figures — Malick Gakou of the Grand Parti and Thierno Bocoum of the Agir movement — were among those arrested, their parties said.

Idrissa Seck, who headed the government between 2002 and 2004, was also arrested while "en route for the Assembly," said an official from his Rewmi party, Mbacke Seck. Kilifa, a popular rapper and political activist, was also detained.

Around 100 demonstrators who had barricaded a street near parliament were dispersed by tear gas, AFP journalists reported.

Police also fired tear gas at around 50 protestors who were throwing stones at a police vehicle.

Protests were also held in the northern town of Saint-Louis, Thies in the west and the central city of Mbacke.

The first round of the presidential election in the West African country seen as a regional beacon of democracy is scheduled for February 24, 2019.

Meanwhile in the National Assembly, under the protection of riot police, deputies started debating a law requiring all presidential candidates to collect the signatures of at least one percent of the electorate to be able to stand.

The draft legislation, aimed at "furthering democracy" and drawn up by President Macky Sall, was approved in committee in the Assembly on Monday.

Sall, elected in 2012, is seen as the favourite to win next year's election.

"The sole aim of this is evident to everybody: to prevent opposition candidates from contesting," the opposition coalition said.

Rights monitor Amnesty International meanwhile urged Senegal to "respect the right of people to demonstrate peacefully and to air their opinions against a backdrop of repression."

The authorities say they fear an inflation in the number of presidential candidates in a country with nearly 300 parties, recalling the 47 lists that contested legislative elections in July 2017.